Latex rubber

Rubber compounds Rubber content Rubber latex... 

L tex Foa.m Rubber. Latex foam mbber was the first ceUular polymer to be produced by frothing. (/) A gas is dispersed in a suitable latex 2) the mbber latex particles are caused to coalesce and form a continuous mbber phase in the water phase (7) the aqueous soap film breaks owing to... 

Speciali dElastomers bulletins, Eirestone Synthetic Rubber Latex Co., Akron, Ohio. 

Rubber processed in latex form accounts for about 10% of new mbber consumption. Rubber latex is a Hquid, oil-in-water emulsion which is used to make foam or thin-walled mbber articles. The same accelerators and antidegradants used in dry mbber are used in latex, with longer-chain versions preferred for greater oil solubiHty. To prepare these and other additives for addition to latex, they must be predispersed in water and the surface of the powder or oil droplet coated with a surface-active agent to prevent destabilization (coagulation) of the latex. 

The compounding technique for latex differs from that of dry mbber and is fundamentally simpler. A critical factor of colloidal stabiUty makes necessary that each ingredient is of optimum particle size, pH, and concentration when added as an aqueous dispersion to the latex. Rubber latex is a colloidal aqueous emulsion of an elastomer and natural mbber latex is the milky exudation of certain trees and plants that of greatest commercial importance is the... 

Fig. 1. Routes by which natural rubber latex is converted into traditional sheet and crepe.

Table 11. ISO Specifications for Natural Rubber Latex Concentrates...

Type of dryer tions, extracts, milk, blood, waste liquors, rubber latex, etc. gents, calcium carbonate, bentonite, clay sbp, lead concentrates, etc. trifuged sobds, starch, etc. dry. Examples centrifuged precipitates, pigments, clay, cement. ores, potato strips, synthetic rubber. objects, rayon skeins, lumber. sheets. her sheets. 

Deformation of a suspension. This is of great importance with rubber latex and other latices and with PVC paste. 

Poly(acrylic acid) is insoluble in its monomer but soluble in water. It does not become thermoplastic when heated. The sodium and ammonium salts have been used as emulsion-thickening agents, in particular for rubber latex. The polymer of methacrylic acid (Figure 15.13 (VI)) is similar in properties. 

The polymer is a water-soluble viscous liquid which has found application in the adhesive and rubber industries. One particular use has been a heat sensitiser used in the manufacture of rubber latex dipped goods. 

Spandex fibres, because of their higher modulus, tensile strength and resistance to oxidation, as well as their ability to be produced at finer deniers, have made severe inroads into the natural rubber latex thread market. They have also enabled lighter weight garments to be produced. Staple fibre blends with non-elastic fibres have also been introduced. 

Today polyether foam with a density of less than half that of rubber latex foam is widely used as a cushioning material. Polyester foams, although tending to be more expensive, continue to have a number of outlets, particularly where a high initial modulus is desirable. In addition to miscellaneous upholstery applications... 

Casein is used for a number of miscellaneous purposes in which foimolisation is not required. These include adhesives, stabilisers for rubber latex, paper finishing agents and miscellaneous uses in the textile industry. Mention may also be made of casein fibres, available in Italy between the two world wars under the name of Lanital. 

Natural rubber latex Latex gloves, adhesives, surgical apparatus and appliances... 

For applications where surgical gloves provide adequate protection, if these are of natural rubber latex tlien powder-free gloves witli low/undetectable protein and allergen levels are advisable. (Alternatively the use of nitrile gloves eliminates the risk of latex allergy.)... 

Gazeley. K.F. and Mente, P.G., Pressure-sensitive adhesives from modified natural rubber latex. Adhesives, Sealants and Encapsulants Conference, Kensington, London, 5th November, 1985. 

Chemical Designations - Synonyms Plastic latex Synthetic rubber latex Chemical Formula Not pertinent. 

Synthetic rubber latex was made by a process with a large and hazardous inventory of butadiene and styrene. In a modified process, the reactor has an initial charge of water and emulsifier. Also, the monomers are added to the reactor as one premixed stream and the emulsified aqueous sodium persulfate is added as the other stream. The improved scheme, discussed by Englund (1991a) contains less hazardous material and at a lower, more controllable temperature. It illustrates that large and established processes may be made safer by applying inherent safety. 

Vulcanization of natural rubber latex by heating it with S diseovered by Charles Goodyear (USA). 

The available studies indicate that diimide has been used as a reducing agent for the preparation of HNBR. It has been used mainly as an alternative for hydrogenation of nitrile rubber latex. The use of diimide to hydrogenate low-molecular weight olefines is well known in the organic literature [93]. Diimide can be conveniently generated in situ by thermal treatment of solutions of p-tolu-enesulfonyl hydrazide or oxidation of hydrazine. 

There are many temporary protectives on the market and it would be impracticable to describe them individually. However, they may be classified according to the type of film formed, i.e. soft film, hard film and oil film the soft film may be further sub-divided into solvent-deposited thin film, hot-dip thick film, smearing and slushing types. All these types are removable with common petroleum solvents. There are also strippable types based on plastics (deposited by hot dipping or from solvents) or rubber latex (deposited from emulsions) these do not adhere to the metal surfaces and are removed by peeling. In addition there are volatile corrosion inhibitors (V.C.I.) consisting of substances, the vapour from which inhibits corrosion of ferrous metals. 

Rubber latex cement Rubber latex cement consists of mixtures of sand and other fillers which are gauged with rubber latex solution. These cements are suitable for dilute acid conditions and are particularly useful in conditions where dilute acid alternates with water or dilute alkalis. They remain very slightly resilient and adhere very well to stoneware. They are not of course... 

Emulsion polymerization is the most important process for production of elastic polymers based on butadiene. Copolymers of butadiene with styrene and acrylonitrile have attained particular significance. Polymerized 2-chlorobutadiene is known as chloroprene rubber. Emulsion polymerization provides the advantage of running a low viscosity during the entire time of polymerization. Hence the temperature can easily be controlled. The polymerizate is formed as a latex similar to natural rubber latex. In this way the production of mixed lattices is relieved. The temperature of polymerization is usually 50°C. Low-temperature polymerization is carried out by the help of redox systems at a temperature of 5°C. This kind of polymerization leads to a higher amount of desired trans-1,4 structures instead of cis-1,4 structures. Chloroprene rubber from poly-2-chlorbutadiene is equally formed by emulsion polymerization. Chloroprene polymerizes considerably more rapidly than butadiene and isoprene. Especially in low-temperature polymerization emulsifiers must show good solubility and... 

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